Web-cutting apparatus

ABSTRACT

This application describes web cutting apparatus comprising a rotary drum having a substantially radially inwardly extending shaped slot in its periphery, drive means for driving said drum, a cutter arm, cam means which is adapted to control the movements of said cutter arm and which is connected to be driven by said drive means, the control of the cam means and the shape of the cutter arm being such that in operation the cutter arm will cut through a web on said drum at said slot and will descend, together with the leading edge of the trailing portion of the cut web, into said slot and remain in the said slot for a predetermined period.

nited States atent Chapman [451 June 13, 1972 WEB-CUTTING APPARATUS Inventor: Eric George Arthur Chapman, llford, En-

gland Assignee: llford Limited, Ilford, England Filed: May 12, 1970 Appl. No.: 36,595

Foreign Application Priority Data References Cited UNITED STATES PATENTS Roksvaag ..83/337 X 2,379,033 6/1945 Olsson ..83/ 337 2,445,843 7/1948 Tumer....

370,672 9/1887 Bacon.....

Rl3,486 11/1912 Laukhuff ..83/337 X Primary ExaminerFrank T. Yost Attorney-Cushman, Darby & Cushman [57] ABSTRACT This application describes web cutting apparatus comprising a rotary drum having a substantially radially inwardly extending shaped slot in its periphery, drive means for driving said drum, a cutter arm, cam means which is adapted to control the movements of said cutter arm and which is connected to be driven by said drive means, the control of the cam means and the shape of the cutter arm being such that in operation the cutter arm will cut through a web on said drum at Said slot and will descend, together with the leading edge of the trailing portion of the cut web, into said slot and remain in the said slot for a predetermined period.

4 Claims, 5 Drawing Figures PATENTEUJUH 13 m2 SHEET 1 BF 3 m/meum/z 62/4 Gambia/WW2 U/mwm/ 63/ MM. [0M4 WEB-CUTTING APPARATUS This invention relates to web cutting apparatus, and although it is not so restricted, it is concerned particularly with apparatus for cutting a perforated web of limited width, e.g. film, while the web is in motion.

According to the present invention, there is provided web cutting apparatus comprising a rotary drum having a substantially radially inwardly extending shaped slot in its periphery, drive means for driving said drum, a cutter arm, cam means which is adapted to control the movement of said cutter arm and which is connected to be driven by said drive means, the control of the cam means and the shape of the cutter arm being such that in operation the cutter arm will cut through a web on said drum at said slot and will descend, together with the leading edge of the trailing portion of the cut web, into said slot and remain in the said slot for a predetermined period.

The control of the cam means is preferably such that, while in said slot, the cutter arm continues its descent to overrun the said leading edge, and thereafter, at a predetermined period, rises from said slot and guides the said leading edge into a position in which the latter is aligned with a dispensing aperture.

Moreover, the control of the cam means may be advantageously such that after the cutter arm has risen out of said slot, it is lifted so as to be well clear of the drum over an angle which is a function of the angle subtended by the normals drawn to the respective tangents of the web run-on and run-off positions on the drum.

The cam means preferably includes a stationary cam track, and a cam follower mounted on a lever attached to a shaft mounted through the drum for rotation therewith, there being a bevel gear connection between the mounting of the cam follower and the cutter arm.

i The drum may have associated therewith cam-driven control means for positioning the web on the drum and for engaging the lateral edges of the web after the cutter arm has cut through the web.

.The drum has preferably at least one set of peripheral teeth for co-operating with perforations in said web.

The invention will now be described, merely by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of the web cutting apparatus according to the present invention,

FIG. 2 is a section taken along the line B-B of FIG. 1 and illustrating the stationary cam track,

FIG. 3 is a section taken along the line E-E of FIG. 1,

FIG. 4 is a fragmentary perspective view of the cutter arm of the apparatus shown in FIG. 1, but on an enlarged scale, and

FIG. 5 is a view in half section of the cam-driven control means associated with the apparatus of FIG. 1 for positioning the web on the apparatus according to the present invention.

Referring to the drawings, there is shown a web cutting apparatus which includes a central drive shaft 11 adapted to be connected and driven by a prime mover (not shown).

- The web cutting apparatus 10 may form part of a larger apparatus (not shown) such as an auto-spooling machine which may include a stock of film which is continuously fed to a drum associated with cutting means, to be described below, for cutting the film into predetermined lengths while it is running, an indexing mechanism, a tape sticking mechanism associated with the indexing mechanism for feeding adhesive tape to a tape measuring drum, a tape cutter for periodically severing a predetermined length of tape ofi the tape on the drum and thereafter sticking that predetermined length of tape onto the trailing edge of a length of severed film so as to secure said film to a backing web, and thereafter feeding the film and the backing web to a spooling or winding mechanism and a spool-ejecting mechanism.

Accordingly, FIG. 1 shows a gear arrangement generally indicated at 12 for transmitting drive from the drive shaft 11 to at least some of the above-mentioned other parts of the larger apparatus.

The shah 11 is joumalled in a pair of spaced apart ball bearings 14 and 15 the outer races of which are connected to stationary support structure 16. The support structure 16 has at its front end (i.e. the right-hand end as viewed in FIG. 1) an integral peripheralflange 17 to which issecured a stationary cam (the knife cam) 18 having a cam track 19 therein. One purely exemplary embodiment of the shape of the cam track 19 is shown in FIG. 2.

Keyed to the front end of the shaft 11 is a drum 21 having a set of angularly spaced apart peripheral teeth 22. The web or film to be cut is fed by means not shown from a stock onto the drum 21 so that the perforations in the film engage over the teeth 22 on the drum 21 whereby accurately to position the web on the drum 21. Also indicated is another cam 50 (web positioning cam) having therein a cam track 51. This is shown in greater detail in FIG. 5.

As can be seen most clearly in FIG. 3, the drum 21 is provided with a radially extending slot 25 of substantially rectangular cross-section. An arrow 26 indicates in FIG. 3 the direction of rotation of thedrum 21. As can be seen, the slot 25 is formed with a rounded trailing edge 27 and with a substantially straight leading edge 28. At the leading edge 28 a stationary cutter element 29 is secured to the radially extending trailing face of the slot 25 and such that the operative edge of the stationary cutter 29 coincides with the longitudinal center line 30 of the slot 25.

Mounted on the shaft 11 and the drum 21 is a cutter arm generally indicated at 35, the actual shape of which can be seen better and on an enlarged scale on FIG. 4. Secured to the base of the cutter arm 35 is a bevel gear wheel 37 which has, preferably, spiral teeth. The bevel gear 37 is in meshing engagement with another bevel gear 38 of spiral teeth and mounted fixedly at the front end of a shaft 39 on the rear end of which is mounted a cam follower generally indicated at 40 which engages in the cam track 19.

Referring now to FIG. 4, it will be seen that the cutter arm 35 has at its free end a front or cutting edge 42 adapted to cut the web by co-operation with the stationary cutting element 29, and an enlargement 43 at its trailing edge.

Referring now to FIG. 5, there is shown a fragmentary half sectional view of another stationary cam plate 50 having therein a cam track 51 in which is engaged a cam follower generally-indicated at 52. The cam follower 52 is adapted to be driven by the drum 21, the connection being shown at 53. From the connection 53 a respective pair of pivoted link arms 54, 55 extend to the two axial end faces of the drum 21, and the respective free ends of the pivoted link arms 54, 55 terminate in respective reciprocable fingers 56. The fingers 56 are adapted to engage the lateral edges of the severed film 60 on the surface of the drum 21 by extending between a pair of adjacent teeth 22, so as to control the position of the film 60 on the drum 21. Also indicated is the knife cam 18, the cam track 19 and the knife 35.

The operation of the web cutting apparatus is as follows. By means not shown, perforated film is fed onto the drum 21 so that the perforations in the film engage over the teeth 22. Shaft 11 causes the drum 21 to rotate, and this drive is transmitted also to the cutter arm 35 through the cam track 19 and the cam follower 40. The shape of the cam track 19 is such that at the beginning of each cycle of operation the cutter arm 35 extends radially and well clear of the drum 21 and will move inwardly towards the drum 21. At a predetermined angular location the cutter arm 35 will engage the web and cut through it, and at this predetermined location the slot 25 in the drum 21 will be exactly opposite the cutter arm 35. As the cutter arm 35 slices through the web of film, a small ripple is formed in the film, but the cam and follower arrangement 50, 51 and 52 is such that that moment the fingers 56 engage the lateral edge of the severed film 60.

As the drum 21 continues to rotate, the cutter arm 35 will descend into the slot 25 and in doing so its enlarged trailing end 43 will engage the leading edge of the film on the drum to press that leading edge against the rounded edge 27 of the slot 25 to prevent it from interfering with a subsequent operation.

As the drum 21 continues to rotate, the cutter arm 35 in the slot 25 overruns the leading edge of the severed film 60, and after a predetermined period begins its return stroke and rises out of the slot.

Clearly as the cutter arm 35 begins to rise out of the slot 25 it will once again engage the leading edge of the severed film and the fingers 56 release the film but this time is will engage it with its flat top surface 44 so as to guide the said leading edge. Although this is not shown, in fact the leading edge will be guided into the aperture defined between a pair of closely spaced chute members which lead to a dispensing and spooling mechanism (not shown).

The return or rising movement of the cutter arm 35 will continue until it is once again clear of the drum 21, as shown in FIG. 1, so as to prevent it from interfering with various associated parts, such track 19 is such that the cutter arm 35 will be clear of the drum 21 over an angle which is a function of the angle subtended by the normals to the tangents to the drum drawn at the run-on and run-off points of the web.

As will be appreciated, the illustrated embodiment of the present invention provides a relatively simple web cutting apparatus capable of cutting off predetermined lengths from a continuous web while the latter is moving and in which the cutter arm performs the double function of cutting the web and thereafter controlling it so as to prevent it from interfering with previously cut lengths and then to guide it into a desired predetermined direction.

I claim as my invention:

1. Web cutting apparatus comprising a rotary drum having a substantially radially inwardly extending shaped slot in its periphery, drive means for driving said drum, a cutter arm, cam means adapted to control the movements of said cutter arm and drivably connected to said drive means, the control of the cam means and the shape of the cutter arm being such that in operation the cutter arm cuts through a web on said drum at said slot and descends, together with the leading edge of the trailing portion of the cut web, into said slot and continues its descent to overrun the said leading edge, and thereafter, at a predetennined period, rises from said slot and guides the said leading edge into a position in which the latter is aligned with a dispensing aperture.

2. Web cutting apparatus according to claim 1 wherein the control of the cam means is such that after the cutter arm has risen out of said slot, it is lifted so as to be well clear of the drum over an angle which is a function of the angle subtended by the normals drawn to the respective tangents of the web run-on and run-off positions on the drum.

3. Web cutting apparatus according to claim 1 wherein the cam means includes a stationary cam track, and a cam follower mounted on a lever attached to a shaft mounted through the drum for rotation therewith, there being a bevel gear connection between the mounting of the cam follower and the cutter arm.

4. Web cutting apparatus according to claim 1 wherein the drum has associated therewith cam-driven control means for positioning the web on the drum and for engaging the lateral edges of the web after the cutter arm has cut through the web. 

1. Web cutting apparatus comprising a rotary drum having a substantially radially inwardly extending shaped slot in its periphery, drive means for driving said drum, a cutter arm, cam means adapted to control the movements of said cutter arm and drivably connected to said drive means, the control of the cam means and the shape of the cutter arm being such that in operation the cutter arm cuts through a web on said drum at said slot and descends, together with the leading edge of the trailing portion of the cut web, into said slot and continues its descent to overrun the said leading edge, and thereafter, at a predetermined period, rises from said slot and guides the said leading edge into a position in which the latter is aligned with a dispensing aperture.
 2. Web cutting apparatus according to claim 1 wherein the control Of the cam means is such that after the cutter arm has risen out of said slot, it is lifted so as to be well clear of the drum over an angle which is a function of the angle subtended by the normals drawn to the respective tangents of the web run-on and run-off positions on the drum.
 3. Web cutting apparatus according to claim 1 wherein the cam means includes a stationary cam track, and a cam follower mounted on a lever attached to a shaft mounted through the drum for rotation therewith, there being a bevel gear connection between the mounting of the cam follower and the cutter arm.
 4. Web cutting apparatus according to claim 1 wherein the drum has associated therewith cam-driven control means for positioning the web on the drum and for engaging the lateral edges of the web after the cutter arm has cut through the web. 